In a wireless communication system, both sides of transmitter and receiver can use a plurality of antennas for communication transmission, namely the multiple-input multiple-output (MIMO) technique. If channels between respective transmit and receiving antennas are independent of each other, then a plurality of parallel spatial channels can be created in a communication system using the MIMO technique. And a wireless communication system, especially a cellular wireless communication system, can be enhanced in terms of capacity and coverage by independently transmitting information via these parallel spatial channels. However, for the cellular wireless system with small frequency reuse factor, especially for frequency reuse factor of 1, benefits of capacity gain or diversity gain from MIMO will be degenerated significantly due to relatively low signal to interference plus noise power ratio (SINR) at the cell edge. As a matter of fact, noise and multi-path fading are dominant factors behind wireless channel distortion in the cell center, and serious inter-cell interference (ICI) is the dominant factor in affecting channels at the cell edge where SINR is usually less than 0 dB.
The inter-cell interference cancellation methods that have been disclosed till now include a repetition code method proposed by Hiroyuki Atarashi on “Broadband packet wireless access based on VSF-OFCDM and MC-DS-CDMA” Proceedings of PIMRC 2002, a dynamical scheduling method proposed by ALCATEL on 3GPP R1-050594, “Multi-cell Simulation Results for Interference Coordination in new OFDM DL,” and a MIMO based macro diversity method proposed on IEEE 802.16e/D9 in July 2005. The repetition code method ensures a wireless communication system using MIMO to operate in the range of low SINR by achieving code gain, which is at the cost of bandwidth efficiency. The dynamical scheduling method coordinates ICI by allocating orthogonal channel resource (frequency bands for an OFDM system) to the users at the cell edge, thereby avoiding interference to the users in neighboring cells. However, it results in complex coordination operations among related transmitters and low channel usage efficiency at the cell edge. This method is also at the cost of channel usage efficiency and base station complexity. The MIMO based macro diversity method transmits the same data streams jointly from a plurality of relevant transmitters at the cell edge, and hence it avoids ICI and achieves diversity. However, just like the dynamic scheduling method, it causes problems, such as low channel usage efficiency and base station complexity.
To sum up, existing interference cancellation methods for wireless communication systems cannot effectively avoid ICI without increasing base station (transmitter) complexity and/or decreasing low spectrum usage efficiency.